Tom and Dave, thank you both. Build threads are always my favorite to follow on forums, so I would be remiss if I didn't share my own. The most I could ask for is to inspire someone to build something of their own.
I applied the roof sheets to the car last night (1/16" thick wood sheet), and let the glue set over night. Like the side sheathing, I purposefully cut it rough extending too far out from the sides. I then used a piece of 1/16" scrap sheet, taped to the side of the car, as a spacer and sanded the edge flat and parallel to the car side. I neglected to take a photo before doing this, so I staged the one below to show the concept.
After sanding the roof sheets, I applied the roof trim. On the sides is a scale 2x4, running the length of the car between the corner posts. The end trim was made of 1/16" square stock, sanded flush to the sheets with the sanding block. I had to notch out the Zee bars to fit the end trim.
Next up is some wood filler to cover the seam along the crest of the roof and in the trim pieces, and a coat of sanding sealer.
~Chris